Werk #22424: Windows service discovery: an invalid pattern no longer breaks discovery
| Component | Checks & agents | ||||||
| Title | Windows service discovery: an invalid pattern no longer breaks discovery | ||||||
| Date | Sep 22, 2026 | ||||||
| Level | Trivial Change | ||||||
| Class | Bug Fix | ||||||
| Compatibility | Compatible - no manual interaction needed | ||||||
| Checkmk versions & editions |
|
The rule Windows service discovery expects regular expressions. If one of the
patterns was not a valid regular expression, for example the shell style
*SQL* instead of .*SQL, the service discovery of the whole host failed
with error: nothing to repeat at position 0. The Check_MK Discovery service
reported a crash and no service on that host could be discovered any more.
Two things change:
- Setup now rejects an invalid regular expression when the rule is saved and says what is wrong with it, so the mistake is caught where it is made.
- An invalid pattern in an existing rule no longer stops the discovery. It matches nothing, and the other patterns of the rule and all other hosts are discovered as before.
An existing rule with an invalid pattern therefore discovers fewer services than intended without saying so. If services are missing after this update, open the rule and save it again: the pattern that is rejected is the one that never matched.